CN104340212B - Vehicle and vehicle control method - Google Patents

Abstract

In a vehicle and a vehicle control method, when conditions i) and ii) are satisfied, an electronic control unit is configured to control an internal combustion engine so as to delay starting of the internal combustion engine, which is based on a condition where a vehicle request power is greater than a start threshold value, in a first mode than that in a second mode. The condition i) is a condition in which the driving mode is the first mode and the condition ii) is a condition in which the vehicle request power requested by the vehicle is greater than the start threshold value. The start threshold value is a value with which the internal combustion engine in a stopped state is started.

Description

Vehicle and vehicle control method

technical field

The present invention relates to a hybrid vehicle equipped with a rotary electric machine and an internal combustion engine and a vehicle control method.

Background technique

Japanese Patent Application Publication No. 2010-234872 (JP 2010-234872 A) discloses a hybrid vehicle in which when the vehicle required power is greater than the starting threshold of the internal combustion engine, the internal combustion engine Start inside.

The hybrid vehicle can travel in any one of various driving modes including the vehicle continuously performing motor driving using only the driving motor without maintaining the state of charge (SOC) of the power storage device and a driving mode in which the vehicle runs with the internal combustion engine while maintaining the SOC of the power storage device. In such a hybrid vehicle, in order to secure driving power regardless of the driving mode, the internal combustion engine may be started when the vehicle demanded power is greater than a starting threshold. Therefore, for example, when the vehicle required power is temporarily greater than the start threshold due to irregular operation of the accelerator by the driver, etc., the drive mode for maintaining motor drive is selected, but the internal combustion engine may start against the driver's intention.

Contents of the invention

The present invention provides a vehicle and a vehicle control method that appropriately controls the start of an internal combustion engine according to the state of a hybrid vehicle.

A vehicle according to the present invention includes: a rotating electrical machine; an internal combustion engine; a power storage device; and an electronic control unit. The rotary electric machine and the internal combustion engine are configured to generate driving force for the vehicle. The power storage device is configured to supply electric power to the rotating electric machine. The electronic control unit is configured to control the rotary electric machine and the internal combustion engine in any one of a plurality of driving modes including a first mode and a second mode, the first The first mode is a mode in which the vehicle travels using electric power of the power storage device without maintaining a state of charge of the power storage device, and the second mode is a mode in which the vehicle maintains a state of charge of the power storage device. driving mode. When the following conditions i) and ii) are met, the electronic control unit is configured to control the internal combustion engine to delay the start of the internal combustion engine than in the second mode, the start of the internal combustion engine being based on vehicle demand the condition that the power is greater than the start threshold: i) the condition that the driving mode is the first mode; and ii) the condition that the vehicle demanded power demanded from the vehicle is greater than the start threshold, wherein the start threshold is A value to start the internal combustion engine at a standstill.

A vehicle control method according to the present invention, wherein the vehicle includes a rotary electric machine, an internal combustion engine, an electric storage device, and an electronic control unit. The rotary electric machine and the internal combustion engine generate driving force for the vehicle. The power storage device generates driving force for the rotary electric machine. The vehicle control method includes controlling the rotary electric machine and the internal combustion engine in any one of a plurality of driving modes, including a first mode and a second mode, by the electronic control unit. Two modes, the first mode is a mode in which the vehicle runs using the electric power of the power storage device without maintaining the charging state of the power storage device, and the second mode is a mode in which the vehicle maintains the power storage device mode of simultaneous travel of the state of charge of the device; and when the following conditions i) and ii) are met, the internal combustion engine is controlled by the electronic control unit to delay the start of the internal combustion engine than in the second mode , the starting of the internal combustion engine is based on the condition that the vehicle demanded power is greater than a start threshold: i) the condition that the driving mode is the first mode; and ii) the vehicle demanded power demanded from the vehicle is greater than the starting A condition of a threshold value, wherein the starting threshold value is a value at which the internal combustion engine in a stopped state is started.

According to the invention, when the vehicle demanded power is greater than the start threshold in the first mode, the internal combustion engine is controlled to delay the start of the internal combustion engine than in the second mode, said start of the internal combustion engine being based on the condition that the vehicle demanded power is greater than the start threshold . As a result, even when the vehicle required power is temporarily greater than the start threshold due to the driver's irregular operation of the accelerator in the first mode, the internal combustion engine is prevented from starting at the point when the vehicle required power becomes greater than the start threshold. That is, it is possible to prevent the internal combustion engine from starting against the driver's intention. By delaying the start of the internal combustion engine, the motor drive using only the rotary electric machine can be continuously performed. Therefore, the present invention can provide a vehicle and a vehicle control method capable of appropriately controlling the starting of the internal combustion engine according to the state of the hybrid vehicle.

Description of drawings

The features, advantages and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals indicate like elements, and in which:

FIG. 1 is a block diagram showing the overall configuration of a vehicle;

Fig. 2 is a functional block diagram of an electronic control unit (ECU);

Fig. 3 is a flowchart (first part) showing a control structure of a program executed by the ECU;

FIG. 4 is a flowchart (second part) showing a control structure of a program executed by the ECU; and

FIG. 5 is a timing chart showing the operation of the ECU.

detailed description

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, the same elements are denoted by the same reference numerals. The names and functions of the same elements remain unchanged. Therefore, its detailed description will not be repeated.

An overall block diagram of a hybrid vehicle 1 (hereinafter simply referred to as vehicle 1 ) according to the present embodiment will be described below with reference to FIG. 1 . Vehicle 1 includes a transmission 8 , an engine 10 , a torsional vibration damper 18 , a power/electric control unit (PCU) 60 , a battery 70 , drive wheels 72 , a charging device 78 and an electronic control unit (ECU) 200 .

Transmission 8 includes a drive shaft 16 , a first motor generator (hereinafter referred to as first MG) 20 , a second motor generator (hereinafter referred to as second MG) 30 , a power split device 40 and a reduction gear 58 .

Vehicle 1 travels with driving power output from at least one of engine 10 and second MG 30 . Power generated from engine 10 is divided into two paths by power split device 40 . One of the two paths is a path in which power is transmitted to drive wheels 72 via reduction gear 58 , and the other path is a path in which power is transmitted to first MG 20 .

The first MG 20 and the second MG 30 are, for example, three-phase AC rotating electrical machines. First MG 20 and second MG 30 are driven by PCU 60 .

The first MG 20 has a function of a generator that generates electricity using the power of the engine 10 distributed by the power split device 40 and charges the battery 70 via the PCU 60 . The first MG 20 receives electric power from the battery 70 and rotates a crankshaft which is an output shaft of the engine 10 . Therefore, first MG 20 has a function of a starter that starts engine 10 .

Second MG 30 has a function of a drive motor that supplies drive wheels 72 with drive force using at least one of electric power stored in battery 70 and electric power generated by first MG 20 . In addition, second MG 30 has a function of a generator that charges battery 70 via PCU 60 with electric power generated by regenerative braking.

The engine 10 is an internal combustion engine such as a gasoline engine or a diesel engine and is controlled based on a control signal S1 from the ECU 200 .

The crank position sensor 11 is arranged at a position facing the crankshaft of the engine 10 . The crank position sensor 11 detects the rotational speed Ne of the engine 10 . The crank position sensor 11 transmits a signal indicating the detected rotational speed Ne of the engine 10 to the ECU 200 .

Crank position sensor 11 can detect the rotation angle and angular velocity of the crankshaft of engine 10 , and ECU 200 can calculate the rotational speed Ne of engine 10 based on the rotation angle and angular velocity received from crank position sensor 11 .

In the present embodiment, the engine 10 includes four cylinders 112 from a first cylinder to a fourth cylinder. A spark plug (not shown) is provided on top of each cylinder 112 .

Engine 10 is not limited to the inline four-cylinder engine shown in FIG. 1 . For example, the engine 10 may be various engines including a plurality of cylinders, such as an inline three-cylinder, a V-type six-cylinder, a V-type eight-cylinder, and an in-line six-cylinder.

The engine 10 is provided with a fuel injection device 120 corresponding to each cylinder 112 . The fuel injection device 120 may be provided in each cylinder 112 or may be provided in an intake port of each cylinder.

In engine 10 having this configuration, ECU 200 controls the fuel injection amount to each cylinder 112 by injecting an appropriate amount of fuel into each cylinder 112 at an appropriate timing or stopping fuel injection into each cylinder 112 .

The torsional vibration damper 18 is provided between the crankshaft of the engine 10 and the input shaft of the transmission 8 . The torsional vibration damper 18 absorbs torque fluctuations when power is transmitted between the crankshaft of the engine 10 and the input shaft of the transmission 8 .

Power split device 40 is a power transmission device that mechanically connects three elements of drive shaft 16 that are connected to drive wheels 72 , the output shaft of engine 10 , and the rotation shaft of first MG 20 . The power distribution device 40 utilizes one of the three elements as a reaction element to realize power transmission between the other two elements. The rotation shaft of the second MG 30 is connected to the drive shaft 16 .

The power split device 40 is a planetary gear mechanism including a sun gear 50 , a pinion gear 52 , a carrier 54 and a ring gear 56 . Pinion 52 meshes with sun gear 50 and ring gear 56 . The carrier 54 rotatably supports the pinion gear 52 and is connected to the crankshaft of the engine 10 . The sun gear 50 is connected to the rotation shaft of the first MG 20 . The ring gear 56 is connected to the rotation shaft of the second MG 30 and the reduction gear 58 via the drive shaft 16 .

Reduction gear 58 transmits power from power split device 40 or second MG 30 to drive wheels 72 . Reduction gear 58 transmits the reaction force transmitted from the road surface to drive wheels 72 to power split device 40 or second MG 30 .

PCU 60 converts DC power stored in battery 70 into AC power for driving first MG 20 and second MG 30 . PCU 60 includes a converter and an inverter (both not shown) that are controlled based on a control signal S2 from ECU 200 . The converter boosts the voltage of the DC power supplied from the battery 70 and outputs the boosted voltage to the inverter. The inverter converts the DC power output from the converter into AC power and outputs the AC power to the first MG 20 and/or the second MG 30 . Accordingly, first MG 20 and/or second MG 30 are driven using power stored in battery 70 . The inverter converts AC power generated by the first MG 20 and/or the second MG 30 into DC power and outputs the DC power to the converter. The converter steps down the voltage of the DC power output from the inverter and outputs the stepped down voltage to the battery 70 . Accordingly, the battery 70 is charged using electric power generated by the first MG 20 and/or the second MG 30 . Converters may not be used.

The battery 70 is an electrical storage device and is a rechargeable DC power source. For example, a nickel metal hydride or lithium ion secondary battery is used as the battery 70 . The voltage of the battery 70 is, for example, about 200V. Battery 70 may be charged using power generated by first MG 20 and/or second MG 30 as described above and may also be charged using power supplied from an external power source (not shown). The battery 70 is not limited to a secondary battery, but may be a device capable of generating a DC voltage, such as a capacitor, a solar cell, and a fuel cell. The vehicle 1 may be provided with a charging device capable of charging the battery 70 using an external power source.

ECU 200 estimates the SOC of battery 70 based on the current, voltage, and battery temperature of battery 70 . The ECU 200 may estimate an open circuit voltage (OCV) based on, for example, current, voltage, and battery temperature and may estimate the SOC of the battery 70 based on the estimated OCV and a predetermined map. Alternatively, ECU 200 may estimate the SOC of battery 70 by, for example, integrating the charging current and discharging current of battery 70 .

Charging device 78 charges battery 70 using electric power supplied from external power supply 302 by plugging charging plug 300 into vehicle 1 in a state where vehicle 1 is stopped. Charging plug 30 is connected to one end of charging cable 304 . The other end of charging cable 304 is connected to external power supply 302 . The positive terminal of charging device 78 is connected to power line PL that connects the positive terminal of PCU 60 and the positive terminal of battery 70 . The negative terminal of the charging device 78 is connected to a ground line NL that connects the negative terminals of the PCU 60 and the negative terminal of the battery 70 . In addition to or instead of the charging method of supplying power from the external power supply 302 to the battery 70 of the vehicle 1 by contact power supply using the charging plug 300 or the like, a battery that supplies power from the external power supply 302 to the vehicle 1 by non-contact power supply may be used. 70 charging methods, such as resonance method or electromagnetic induction method.

A first resolver 12 is provided in the first MG 20 . First resolver 12 detects rotational speed Nm1 of first MG 20 . First resolver 12 transmits a signal indicative of detected rotational speed Nm1 to ECU 200 .

A second resolver 13 is provided in the second MG 30 . The second resolver 13 detects the rotational speed Nm2 of the second MG 30 . The second resolver 13 transmits a signal indicative of the detected rotational speed Nm2 to the ECU 200 .

The wheel speed sensor 14 detects the rotational speed Nw of the drive wheel 72 . Wheel speed sensor 14 transmits a signal indicative of detected rotational speed Nw to ECU 200 . ECU 200 calculates vehicle speed V based on received rotation speed Nw. ECU 200 may calculate vehicle speed V based on rotation speed Nm2 of second MG 30 instead of rotation speed Nw.

Accelerator pedal 160 is provided in the driver's seat. The accelerator pedal 160 is provided with a pedal stroke sensor 162 . Pedal stroke sensor 162 detects degree of stroke AP of accelerator pedal 160 (operation amount of accelerator pedal). Pedal stroke sensor 162 transmits a signal indicative of stroke degree AP to ECU 200 . An accelerator pedal depression force sensor for detecting the depression force of the driver of the vehicle 1 on the accelerator pedal 160 may be used instead of the pedal stroke sensor 162 .

The ECU 200 generates a control signal S1 for controlling the engine 10 and outputs the generated control signal S1 to the engine 10 . The ECU 200 generates a control signal S2 for controlling the PCU 60 and outputs the generated control signal S2 to the PCU 60 .

The ECU 200 controls the overall operation of the hybrid system—that is, the state of charge and discharge of the battery 70 and the operating states of the engine 10, the first MG 20, and the second MG 30—by controlling the engine 10, the PCU 60, and the like to allow A controller for the vehicle 1 to travel most efficiently.

ECU 200 calculates vehicle required power corresponding to degree AP of accelerator pedal 160 and vehicle speed V provided in the driver's seat. The ECU 200 requests power from the vehicle when the auxiliary device is actuated, plus the power required for the actuation of the auxiliary device. Here, the auxiliary device is, for example, an air conditioner. ECU 200 controls the torque of first MG 20 , the torque of second MG 30 and the output power (output power) of engine 10 based on the calculated vehicle required power.

In the present embodiment, the ECU 200 is in a drive mode in which the vehicle runs on electric power of the battery 70 without maintaining the SOC of the battery 70 (hereinafter referred to as a depleted charge (CD) mode) and the engine 10 is activated or stopped while the vehicle is maintaining the battery 70. Any one of the driving modes of simultaneous travel at an SOC of 70 (hereinafter referred to as charge maintenance (CS) mode) controls the PCU 60 and the engine 10 . The driving mode may include other driving modes than the CD mode and the CS mode.

ECU 200 automatically switches the drive mode, for example, to CD mode and CS mode. ECU 200 controls PCU 60 and engine 10 in the CD mode when the SOC of battery 70 is greater than threshold SOC(1), and controls PCU 60 and engine 10 in CS mode when the SOC of battery 70 is less than threshold SOC(1), for example. ECU 200 can manually switch the drive mode between CD mode and CS mode.

When the vehicle 1 is running in the CD mode, the operation of the engine 10 for power generation is suppressed and the SOC of the battery 70 is allowed to drop. Therefore, the SOC of the battery 70 is not maintained, the power of the battery 70 is consumed as the running distance increases, and thus the SOC of the battery 70 decreases.

ECU 200 controls PCU 60 so that vehicle 1 travels with the output power of second MG 30 when the vehicle required power is not greater than start threshold Pr(1) of engine 10 in the CD mode.

When the vehicle 1 runs in the CD mode using only the output power of the second MG 30, it is determined that the vehicle required power is greater than the starting threshold Pr(1) of the engine 10, that is, the output power of the second MG 30 cannot meet the vehicle required power . Therefore, ECU 200 starts engine 10 and controls PCU 60 and engine 10 so that the output power of second MG 30 and the output power of engine 10 satisfy the vehicle required power. That is, the CD mode is a drive mode in which the operation of the engine 10 for power generation is suppressed but the engine 10 can be operated to satisfy the power required by the vehicle.

When the vehicle 1 is traveling in the CS mode, the engine 10 can be operated to generate electricity. That is, by operating the engine 10 to maintain the SOC of the battery 70 or restore the SOC of the battery 70 , the decrease in the SOC of the battery 70 is suppressed.

ECU 200 may perform, for example, charge and discharge control of battery 70 in the CS mode so that the SOC of battery 70 is within a predetermined control range. The predetermined control range is, for example, a control range including the above-mentioned threshold SOC(1). ECU 200 may perform charge and discharge control of battery 70 such that the SOC of battery 70 is maintained at a predetermined target SOC. The target SOC is, for example, the threshold SOC(1).

The charging control of battery 70 includes charging control using regenerative electric power generated by regenerative braking of second MG 30 and charging control using electric power generated by first MG 20 using power of engine 10 .

In the CS mode, when the SOC of the battery 70 exceeds a predetermined control range or is much larger than a predetermined target SOC and when the vehicle required power is not greater than the starting threshold Pr(2) of the engine 10, the ECU 200 controls the PCU 60 such that The vehicle runs using only the output power of the second MG 30 .

When the vehicle 1 is running in the CS mode using only the output power of the second MG 30 as described above, it is determined that the vehicle required power is greater than the starting threshold Pr(2) of the engine 10, that is, cannot be driven with the output power of the second MG 30. Meet the power requirements of the vehicle. Therefore, ECU 200 starts engine 10 and controls PCU 60 and engine 10 so that the output power of second MG 30 and the output power of engine 10 satisfy the vehicle required power. That is, the CS mode is a drive mode in which both the operation of the engine 10 for power generation and the operation of the engine 10 for satisfying the vehicle required power are possible.

In this example, the activation threshold Pr(1) in CD mode is greater than the activation threshold Pr(2) in CS mode, but the activation threshold Pr(1) in CD mode can be equal to the activation threshold in CS mode Threshold Pr(2). The starting thresholds Pr(1) and Pr(2) are less than or equal to the upper limit value of the output power of the second MG 30 and less than or equal to the upper limit value of the output power of the battery 70 (Wout).

In the vehicle having the above-described configuration, when the vehicle requires power greater than the starting threshold to ensure driving power, the engine 10 can be started regardless of the driving mode. Thus, for example, when the driver's operation of the accelerator is erratic, the vehicle required power may temporarily be greater than the start threshold. In this case, although the CD mode for continuously performing motor driving is selected, the engine 10 may be started against the driver's intention.

Therefore, in the present embodiment, when the vehicle demanded power is greater than the start threshold in the CD mode, the ECU 200 controls the engine 10 to delay the start of the engine 10 based on the vehicle demanded power being greater than the start threshold than in the CS mode. Threshold condition.

Specifically, when the vehicle demanded power is greater than the start threshold of the engine 10 in the CD mode, the ECU 200 calculates the integral value of excess power of the vehicle demand power relative to the start threshold and starts the engine when the calculated integral value is greater than a predetermined value. The engine 10 is controlled to delay the start of the engine 10 than in the CS mode.

In the present embodiment, when the vehicle required power is greater than the start threshold of engine 10 in the CS mode, ECU 200 starts engine 10 at the point when the vehicle required power becomes greater than the start threshold.

FIG. 2 shows a functional block diagram of ECU 200 mounted on vehicle 1 according to the present embodiment. ECU 200 includes mode determination unit 202 , vehicle required power determination unit 204 , engine temporary start determination unit 206 , integration unit 208 , engine start determination unit 210 and engine start control unit 212 .

The mode determination unit 202 determines whether the current drive mode is the CD mode, that is, whether the current drive mode is the CD mode or the CS mode. The mode determination unit 202 may determine whether the current drive mode is the CD mode, for example, with reference to a predetermined storage area in which information indicating the current drive mode is stored. The mode determination unit 202 may, for example, set the mode setting flag to an ON state when determining that the current drive mode is the CD mode.

Vehicle required power determination unit 204 determines whether the vehicle required power calculated based on accelerator pedal 160 stroke degree AP and vehicle speed V is greater than a start threshold of engine 10 .

In the CD mode, the vehicle required power determination unit 204 determines whether the vehicle required power is greater than the starting threshold Pr(1) corresponding to the CD mode. In the CS mode, the vehicle required power determination unit 204 determines whether the vehicle required power is greater than the activation threshold Pr(2) corresponding to the CS mode. The vehicle required power determining unit 204 may, for example, set the required power determination flag to an on state when determining that the vehicle required power is greater than the starting threshold.

The engine temporary start determination unit 206 sets the engine temporary start determination flag to ON when the drive mode is the CD mode and the vehicle required power is greater than the start threshold Pr(1). The engine temporary start determination unit 206 may set the engine temporary start determination flag to the on state, for example, when both the mode determination flag and the requested power determination flag are set to the on state.

When the engine temporary start determination flag is on, the integration unit 208 calculates the integral value of the excess power of the vehicle required power relative to the start threshold Pr(1) after the engine temporary start determination flag is switched to the on state. Specifically, the integration unit 208 calculates the integral value by, for example, multiplying the excess power by the sampling time and adding the product value for each calculation cycle. This integral value is reset to an initial value (for example, zero) when the engine temporary start determination flag is switched ON or when the engine 10 is started, for example.

The engine start determination unit 210 sets the engine start determination flag to an ON state when the vehicle required power is greater than the start threshold Pr(2) in the CS mode. The engine start determination unit 210 sets the engine start determination flag to an ON state when the integral value calculated by the integration unit 208 is greater than a predetermined value. Engine start determination unit 210 sets the engine start determination flag to an ON state even when the integrated value is not greater than a predetermined value but a predetermined time has elapsed after integration unit 208 starts calculating the integrated value.

The engine start control unit 212 executes the start control of the engine 10 when the engine start determination unit 210 determines that the engine start determination flag is on. Engine start control unit 212 generates control signals S1 and S2 for controlling first MG 20 and engine 10 and transmits the generated control signals to PCU 60 and engine 10 .

Specifically, the engine start control unit 212 starts the engine 10 using the first MG 20 to increase the rotational speed of the engine 10 above the rotational speed at which initial explosion can occur. The engine 10 is operated (started) by performing ignition control and fuel injection control after the rotational speed of the engine 10 becomes higher than or equal to the rotational speed at which initial explosion can occur. The engine start determination flag or the engine temporary start determination flag is switched to an OFF state while, for example, the start control of the engine 10 is being executed.

This embodiment describes that the mode determination unit 202, the vehicle required power determination unit 204, the engine temporary start determination unit 206, the integration unit 208, the engine start determination unit 210, and the engine start control unit 212 are all used as software and by making the CPU of the ECU 200 It is realized by executing a program stored in the memory, but the functional units may be realized by hardware. The program is recorded on a recording medium mounted on the vehicle.

The control structure of the program executed by the vehicle-mounted ECU 200 according to the present embodiment will be described below with reference to FIGS. 3 and 4 .

As shown in FIG. 3, in step (hereinafter referred to as "S") 100, ECU 200 determines whether the current drive mode is the CD mode. When it is determined that the current drive mode is the CD mode (YES in S100), the processing flow goes to S102. Otherwise ("No" in S100), the processing flow goes to S104.

In S102, ECU 200 determines whether or not the vehicle required power is greater than a starting threshold Pr(1) corresponding to the CD mode. When it is determined that the vehicle required power is greater than the startup threshold value Pr(1) corresponding to the CD mode (YES in S102 ), the processing flow goes to S106 . Otherwise ("No" in S102), the processing flow ends.

In S104, ECU 200 determines whether or not the vehicle requested power is greater than a starting threshold Pr(2) corresponding to the CS mode. When it is determined that the vehicle required power is greater than the activation threshold Pr(2) corresponding to the CS mode (YES in S104 ), the processing flow goes to S108 . Otherwise ("No" in S104), the processing flow ends.

In S106, ECU 200 sets the engine temporary start determination flag to an ON state. In S108, ECU 200 sets the engine start determination flag to an ON state.

Referring to FIG. 4 , in S200 , ECU 200 determines whether the engine temporary start determination flag is on. When it is determined that the engine temporary start determination flag is on (YES in S200), the processing flow goes to S202. Otherwise ("No" in S200), the processing flow goes to S210.

In S202, ECU 200 calculates an integral value by integrating the excess power of the vehicle requested power with respect to the starting threshold value Pr(1). The method of calculating the integral value is the same as described above and thus its detailed description is not repeated.

In S204, ECU 200 determines whether the calculated integral value is larger than a predetermined value. When it is determined that the calculated integral value is larger than the predetermined value (YES in S204), the processing flow goes to S206. Otherwise ("No" in S204), the processing flow goes to S208. In S206, ECU 200 sets the engine start determination flag to an ON state.

In S208, ECU 200 determines whether or not a predetermined time has elapsed after the calculation of the integral value was started. When it is determined that the predetermined time has elapsed after the start of the calculation of the integral value (YES in S208), the flow of the process proceeds to S206. Otherwise ("No" in S208), the processing flow goes to S210.

In S210, ECU 200 determines whether the engine start determination flag is on. When it is determined that the engine start determination flag is on (YES in S210), the processing flow goes to S212. Otherwise ("No" in S210), the processing flow ends.

In S212 , ECU 200 executes start control of engine 10 . The start control of the engine 10 is the same as described above and thus a detailed description thereof will not be repeated.

The action of ECU 200 mounted on vehicle 1 according to the present embodiment based on the above-described structure and the above-described flow will be described with reference to FIG. 5 .

For example, assume that the vehicle 1 is traveling at a low speed and with a small accelerator opening in a state where the engine 10 is stopped (engine stop mode) in the CD mode (YES in S100 ). A small accelerator opening means a state in which only the output power of the second MG 30 satisfies the power required by the vehicle. The counter shown in FIG. 5 is a counter for measuring the time after the calculation of the integrated value is started as described above.

When the driver increases the stroke degree AP of the accelerator pedal 160, the vehicle required power increases as the stroke degree AP increases. The output power of the second MG 30 increases as the vehicle required power increases, the actual driving force increases, and the vehicle speed V increases.

When the vehicle required power is greater than the start threshold Pr(1) corresponding to the CD mode at time T(1) (YES in S102 ), the engine temporary start determination flag is set to ON ( S106 ). Since the engine temporary start determination flag is ON (YES in S200), the calculation of the integral value starts (S202). Until the integral value reaches the predetermined value ("No" in S204), the start control of the engine 10 is not performed and thus EV running is continued. Vehicle speed V increases as the output power of second MG 30 increases. Since both the vehicle required power and the vehicle speed V tend to increase, the commanded driving force based on the vehicle required power changes to maintain an almost constant state. On the other hand, since the output power of the second MG 30 is not generated so as to exceed the upper limit value (the output power of the second MG 30 reaches the limit point) as the vehicle speed V increases, the actual driving force increases as the vehicle speed V increases. large and small.

When the integrated value is greater than the predetermined value at time T(2) (YES in S204), the engine start determination flag is set to the ON state (S206). Since the engine start determination flag is on (YES in S210), the start control of the engine 10 is executed (S212), the engine 10 is started, and the engine 10 is in the running mode. When the value of the counter becomes greater than or equal to the predetermined value before the integral value becomes greater than the predetermined value (NO in S204), that is, when the predetermined time elapses after the calculation of the integral value is started (in S208 ("Yes"), the engine start determination flag is set to the ON state (S206).

On the other hand, assume that the vehicle 1 is in the CS mode (NO in S100) in a state where the engine 10 is stopped (that is, in a state where only the output power of the second MG 30 satisfies the vehicle required power) at Drive at low speed and with a small accelerator opening.

When the driver increases the stroke degree AP of the accelerator pedal 160, the vehicle required power increases as the stroke degree AP increases. As the vehicle required power increases, the output power of second MG 30 increases, the actual driving force increases, and the vehicle speed V increases.

When the vehicle required power is greater than the start threshold Pr(2) corresponding to the CS mode (YES in S104 ), the engine start determination flag is set to ON ( S108 ). Since the engine start determination flag is ON ("No" in S200 and "YES" in S210), start control of the engine 10 is executed (S210) and the engine 10 is started.

In this way, the start control of the engine 10 is executed at the point of time when the vehicle required power becomes larger than the start threshold value Pr(2) in the CS mode. On the contrary, in the CD mode, the calculation of the integral value starts when the vehicle requested power becomes larger than the starting threshold Pr(1) and the calculated integral value becomes The starting control of the engine 10 is executed at a point when the value becomes larger than a predetermined value.

In the vehicle according to the present embodiment having the above configuration, when the vehicle required power is greater than the start threshold in the CD mode, the engine 10 is controlled to delay the start of the engine 10 based on A condition in which the vehicle requires power greater than the launch threshold. Assume that the required power of the vehicle in the CD mode is temporarily greater than the start threshold due to irregular operation of the accelerator by the driver. In the vehicle according to the present embodiment, even in this case, it is possible to suppress the engine 10 from starting at the point when the vehicle required power becomes larger than the start threshold and to suppress the engine 10 from starting against the driver's intention. By delaying the start of the engine 10, the motor drive using only the output power of the second MG 30 can be continuously performed. Therefore, it is possible to provide a vehicle capable of appropriately controlling the start of the internal combustion engine according to the state of the hybrid vehicle.

When the driver applies a large force to the accelerator pedal for acceleration, the integral value increases rapidly. Therefore, it is possible to start the engine 10 at an early stage and generate the driving force desired by the driver.

In the CS mode, since the engine 10 is started earlier than in the CD mode, it is possible to quickly start charging the battery 70 and maintain the SOC or recover the SOC.

Modified examples of the present invention will be described below. The above-described embodiments describe that the engine 10 can be operated in the CD mode to ensure driving power, but, for example, the operation of the engine 10 in the CD mode can be prohibited. In this case, ECU 200 may start engine 10 after the drive mode is switched from CD mode to CS mode when the vehicle required power is greater than the start threshold and the integral value is greater than a predetermined value in CD mode.

The above embodiment describes that the cranking of the engine 10 with the first MG 20 starts at the point when the integral value becomes larger than the predetermined value. However, for example, the engine 10 may be cranked up using the first MG 20 to bring the rotation speed of the engine to a rotation speed at which initial explosion can occur before the integral value becomes larger than a predetermined value. Therefore, the engine 10 can be activated quickly at the point when the integral value becomes larger than a predetermined value.

In the above-described embodiments, the case where the driver operates the accelerator irregularly is described as an example of the case where the vehicle required power is temporarily greater than the start threshold. Another example thereof is a case where the traveling road has a large up and down variation (ie, a large difference in height within a short distance) in cruise control that controls the PCU 60 and the engine 10 to keep the speed of the vehicle 1 constant.

The above embodiment describes that the calculation of the integral value starts after the vehicle required power becomes greater than the start threshold value in the CD mode, and the engine 10 is started when the calculated integral value is greater than the predetermined value. For example, after the calculation of the integral value is started, the integral value may be reset to the initial value (zero) whenever the vehicle required power becomes greater than the start threshold.

The above-described embodiment describes the calculation of the integral value only in the CD mode, but the calculation of the integral value may also be started in the CS mode after the vehicle required power becomes greater than the start threshold. In this case, it is preferable that the predetermined value of the integrated value in the CS mode is smaller than the predetermined value of the integrated value in the CD mode. Therefore, the start of the engine 10 based on the condition that the vehicle demanded power is greater than the start threshold can be delayed in the CD mode than in the CS mode.

For example, in S204 of FIG. 4 , when the vehicle requested power is greater than the start threshold in the CD mode, the excess travel relative to a predetermined value (an example of "first value") of the stroke degree AP of the accelerator pedal 160 may be calculated. and the engine 10 can be started when the calculated integral value is greater than a predetermined value (an example of "second value"). The predetermined value of the range AP may be zero or may be the range AP at a point in time when the vehicle requires power greater than a start threshold. With this configuration, it is also possible to delay the start of the engine 10 in the CD mode than in the CS mode, based on the condition that the vehicle demanded power is greater than the start threshold. Alternatively, the start waiting time before engine 10 is started after the vehicle required power becomes greater than the start threshold in the CD mode may be set to be longer than in the CS mode. With this configuration, it is also possible to delay the start of the engine 10 in the CD mode than in the CS mode, based on the condition that the vehicle demanded power is greater than the start threshold. All or part of the modifications described above may be combined and implemented.

The above-described embodiments are illustrative and non-restrictive in all respects. The scope of the present invention is determined not by the above description but by the appended claims, and the present invention is intended to include all modifications having the meaning and scope equivalent to the appended claims.

Claims (8)

1. A vehicle, characterized in that it comprises: a rotating electric machine (30) configured to generate driving force for the vehicle; an internal combustion engine (10) configured to generate driving force for the vehicle; an electric storage device (70) configured to supply electric power to the rotating electric machine; and an electronic control unit (200) configured to control the rotary electric machine and the internal combustion engine in any one of a plurality of driving modes, including a first mode and In the second mode, the first mode is a mode in which the vehicle travels using electric power of the power storage device without maintaining the state of charge of the power storage device, and the second mode is a mode in which the vehicle runs while maintaining the power storage device The mode of driving while the state of charge of the power storage device, When the following conditions i) and ii) are met, the electronic control unit is configured to control the internal combustion engine to delay the start of the internal combustion engine than in the second mode, the start of the internal combustion engine being based on vehicle demand Conditions for power greater than the start threshold: i) a condition that the drive mode is the first mode; and ii) A condition in which the vehicle requested power requested to the vehicle is greater than the start threshold value which is a value at which the internal combustion engine in a stopped state is started. 2. The vehicle of claim 1, wherein When the conditions i) and ii) are satisfied, the electronic control unit is configured to control the internal combustion engine to retard the internal combustion engine than in the second mode by performing the following operations v) and vi). starting, the starting of the internal combustion engine is based on the condition that the vehicle demanded power is greater than the starting threshold: v) an operation of calculating a first integral value, said first integral value being an integral value of excess power of said vehicle demanded power relative to said starting threshold; and vi) Starting operation of the internal combustion engine when the first integral value is greater than a predetermined value. 3. The vehicle of claim 1, wherein When the conditions i) and ii) are met, the electronic control unit is configured to control the internal combustion engine to retard the internal combustion engine than in the second mode by performing the following operations vii) and viii). starting, the starting of the internal combustion engine is based on the condition that the vehicle demanded power is greater than the starting threshold: vii) an operation of calculating a second integral value which is an integral value of an excess value of the operation amount of the accelerator pedal with respect to the first value; and viii) Starting operation of the internal combustion engine when the second integral value is greater than a second value. 4. A vehicle as claimed in any one of claims 1 to 3, wherein When the conditions i) and ii) are satisfied, the electronic control unit is configured to start the internal combustion engine when a predetermined time elapses after the vehicle requested power exceeds the start threshold. 5. A vehicle as claimed in any one of claims 1 to 3, wherein the starting threshold is a value less than or equal to an upper limit value of the output power of the rotating electric machine, said activation threshold in said first mode is a first threshold, and The activation threshold in the second mode is a second threshold and the second threshold is less than the first threshold. 6. A vehicle as claimed in any one of claims 1 to 3, wherein When said conditions i) and ii) are fulfilled, said electronic control unit is configured to start said internal combustion engine. 7. The vehicle according to any one of claims 1 to 3, wherein the electronic control unit is configured to prohibit starting of the internal combustion engine when the driving mode is the first mode, and When the conditions i) and ii) are satisfied, the electronic control unit is configured to start the internal combustion engine after the driving mode is switched from the first mode to the second mode. 8. A vehicle control method, wherein the vehicle includes a rotating electrical machine (30), an internal combustion engine (10), an electrical storage device (70), and an electronic control unit (200), the rotating electrical machine and the internal combustion engine generating driving force for the vehicle, and the power storage device generates driving force for the rotating electric machine, the vehicle control method is characterized by including: The rotary electric machine and the internal combustion engine are controlled by the electronic control unit in any one of a plurality of drive modes, including a first mode and a second mode, the first mode is a mode in which the vehicle runs using electric power of the power storage device without maintaining the state of charge of the power storage device, and the second mode is a mode in which the vehicle runs while maintaining the state of charge of the power storage device the mode of travel; and When the following conditions i) and ii) are met, the internal combustion engine is controlled by the electronic control unit to delay the starting of the internal combustion engine in the second mode, the starting of the internal combustion engine being based on the vehicle required power Conditions greater than the start threshold: i) a condition that the drive mode is the first mode; and ii) A condition in which the vehicle requested power requested to the vehicle is greater than the start threshold value which is a value at which the internal combustion engine in a stopped state is started.